For most Muslims, the big challenge of Ramadan is avoiding food all day. For many, it's giving up smoking or some other bad habit for the month. But for 34-year-old Shahed Amanullah, the hardest part is conducting business as usual while fasting.

As the CEO of a Silicon Valley start-up, Amanullah grapples every day of Ramadan with how to maintain his effectiveness and his acumen while upholding the rules and spirit of fasting. In Silicon Valley's culture of hyper-capitalism, says Amanullah, that's a lot harder than it may sound.

"The fact is, in business, there's always this temptation to embellish--not to lie, but to not give up all your cards or tell all the details," admits Amanullah, as he strokes his goatee. "Ramadan simply reminds me that you have to find a way of doing business without resorting to that. But my question is always, how do you make these two different worlds fit?"

For the past year, Amanullah has been CEO of FreeFor.com, recently renamed Relatia, a dot-com start-up that helps people find like-minded acquaintances wherever they're traveling. And over the last year, the native of Fullerton, Calif., has spent 12-hour days over six, sometimes seven, days a week toiling to turn the company into a thriving business. That's often meant navigating the murky waters of business to get stuff done. And it has been, Amanullah says, a major education in how to make friends and influence people in high places.

In the midst of it all, Ramadan represents a rethinking of how Amanullah lives his life, and it reminds him of his ultimate duties. Indeed, for Amanullah and his other Muslim colleagues and backers in Silicon Valley, Ramadan is a reminder that there's more to life than winning.

Yet conflicts arise in seemingly unlikely ways. Most recently, for example, Amanullah found himself running into trouble as he was working to raise funds for the company. There's always a temptation to exaggerate the company's customer list, calling potential clients who have merely expressed interest in the business "customers," Amanullah says. While fasting, however, Amanullah found himself constantly second-guessing the claims he was making, struggling to tone down any hint of exaggeration. Negotiations are just as tricky, he notes, as the quest for the best deal can often conflict with fasting.

Come Ramadan, Amanullah becomes especially sensitive, even to these seemingly minor fibs. Like many other Muslims, he sees Ramadan as a month of atonement, during which bad habits are noted and squelched in the name of God. In addition to doing without food and water from sunrise to sunset during Ramadan, Muslims must also avoid the normal improprieties of life, be they lying, cussing, or cheating. The hope is that after the 30 days of the month, fasting Muslims will have lost nasty habits and grown spiritually stronger.

"Ramadan has always been an exercise in checking my humility," he says, "I want my people to say 'the head of my company was an honorable man who did right by everyone.'" But most of all, he hopes other Muslims will follow his lead and, in the process, become standard bearers for the way business should be done in Silicon Valley.

"Ramadan means controlling your natural instincts--not just your desire to eat, but also your desire to win, and your desire become wealthy," he notes. "It's a slippery slope, and I often catch myself in it." With the fast during Ramadan comes the quest to fix that, to become a more ethical, maybe even a freer, person.